diff --git a/clang/include/clang/Analysis/CFG.h b/clang/include/clang/Analysis/CFG.h
index e70c70335e59..1b1ff5e558ec 100644
--- a/clang/include/clang/Analysis/CFG.h
+++ b/clang/include/clang/Analysis/CFG.h
@@ -1394,10 +1394,9 @@ public:
   //===--------------------------------------------------------------------===//
 
   template <typename Callback> void VisitBlockStmts(Callback &O) const {
-    for (const_iterator I = begin(), E = end(); I != E; ++I)
-      for (CFGBlock::const_iterator BI = (*I)->begin(), BE = (*I)->end();
-           BI != BE; ++BI) {
-        if (std::optional<CFGStmt> stmt = BI->getAs<CFGStmt>())
+    for (CFGBlock *BB : *this)
+      for (const CFGElement &Elem : *BB) {
+        if (std::optional<CFGStmt> stmt = Elem.getAs<CFGStmt>())
           O(const_cast<Stmt *>(stmt->getStmt()));
       }
   }
diff --git a/clang/lib/Analysis/CFG.cpp b/clang/lib/Analysis/CFG.cpp
index c23e3d057c52..d960d5130332 100644
--- a/clang/lib/Analysis/CFG.cpp
+++ b/clang/lib/Analysis/CFG.cpp
@@ -1753,10 +1753,9 @@ std::unique_ptr<CFG> CFGBuilder::buildCFG(const Decl *D, Stmt *Statement) {
 
   // Add successors to the Indirect Goto Dispatch block (if we have one).
   if (CFGBlock *B = cfg->getIndirectGotoBlock())
-    for (LabelSetTy::iterator I = AddressTakenLabels.begin(),
-                              E = AddressTakenLabels.end(); I != E; ++I ) {
+    for (LabelDecl *LD : AddressTakenLabels) {
       // Lookup the target block.
-      LabelMapTy::iterator LI = LabelMap.find(*I);
+      LabelMapTy::iterator LI = LabelMap.find(LD);
 
       // If there is no target block that contains label, then we are looking
       // at an incomplete AST.  Handle this by not registering a successor.
diff --git a/clang/lib/Analysis/CFGStmtMap.cpp b/clang/lib/Analysis/CFGStmtMap.cpp
index c3a4581e1fb1..028e62ba89b7 100644
--- a/clang/lib/Analysis/CFGStmtMap.cpp
+++ b/clang/lib/Analysis/CFGStmtMap.cpp
@@ -83,8 +83,8 @@ CFGStmtMap *CFGStmtMap::Build(CFG *C, ParentMap *PM) {
 
   // Walk all blocks, accumulating the block-level expressions, labels,
   // and terminators.
-  for (CFG::iterator I = C->begin(), E = C->end(); I != E; ++I)
-    Accumulate(*SM, *I);
+  for (CFGBlock *BB : *C)
+    Accumulate(*SM, BB);
 
   return new CFGStmtMap(PM, SM);
 }
diff --git a/clang/lib/Analysis/CallGraph.cpp b/clang/lib/Analysis/CallGraph.cpp
index 6a2b0392ccea..26646cd6b650 100644
--- a/clang/lib/Analysis/CallGraph.cpp
+++ b/clang/lib/Analysis/CallGraph.cpp
@@ -223,10 +223,7 @@ void CallGraph::print(raw_ostream &OS) const {
   // We are going to print the graph in reverse post order, partially, to make
   // sure the output is deterministic.
   llvm::ReversePostOrderTraversal<const CallGraph *> RPOT(this);
-  for (llvm::ReversePostOrderTraversal<const CallGraph *>::rpo_iterator
-         I = RPOT.begin(), E = RPOT.end(); I != E; ++I) {
-    const CallGraphNode *N = *I;
-
+  for (const CallGraphNode *N : RPOT) {
     OS << "  Function: ";
     if (N == Root)
       OS << "< root >";
diff --git a/clang/lib/Analysis/LiveVariables.cpp b/clang/lib/Analysis/LiveVariables.cpp
index c1b2ff41edc0..375fdb3695e2 100644
--- a/clang/lib/Analysis/LiveVariables.cpp
+++ b/clang/lib/Analysis/LiveVariables.cpp
@@ -546,8 +546,8 @@ LiveVariablesImpl::runOnBlock(const CFGBlock *block,
 
 void LiveVariables::runOnAllBlocks(LiveVariables::Observer &obs) {
   const CFG *cfg = getImpl(impl).analysisContext.getCFG();
-  for (CFG::const_iterator it = cfg->begin(), ei = cfg->end(); it != ei; ++it)
-    getImpl(impl).runOnBlock(*it, getImpl(impl).blocksEndToLiveness[*it], &obs);
+  for (CFGBlock *B : *cfg)
+    getImpl(impl).runOnBlock(B, getImpl(impl).blocksEndToLiveness[B], &obs);
 }
 
 LiveVariables::LiveVariables(void *im) : impl(im) {}
@@ -618,10 +618,8 @@ void LiveVariables::dumpBlockLiveness(const SourceManager &M) {
 
 void LiveVariablesImpl::dumpBlockLiveness(const SourceManager &M) {
   std::vector<const CFGBlock *> vec;
-  for (llvm::DenseMap<const CFGBlock *, LiveVariables::LivenessValues>::iterator
-       it = blocksEndToLiveness.begin(), ei = blocksEndToLiveness.end();
-       it != ei; ++it) {
-    vec.push_back(it->first);
+  for (const auto &KV : blocksEndToLiveness) {
+    vec.push_back(KV.first);
   }
   llvm::sort(vec, [](const CFGBlock *A, const CFGBlock *B) {
     return A->getBlockID() < B->getBlockID();
diff --git a/clang/lib/Analysis/PathDiagnostic.cpp b/clang/lib/Analysis/PathDiagnostic.cpp
index b1fbc3c9eff9..ef24efd3c4bd 100644
--- a/clang/lib/Analysis/PathDiagnostic.cpp
+++ b/clang/lib/Analysis/PathDiagnostic.cpp
@@ -1146,9 +1146,9 @@ void PathDiagnostic::FullProfile(llvm::FoldingSetNodeID &ID) const {
 
 LLVM_DUMP_METHOD void PathPieces::dump() const {
   unsigned index = 0;
-  for (PathPieces::const_iterator I = begin(), E = end(); I != E; ++I) {
+  for (const PathDiagnosticPieceRef &Piece : *this) {
     llvm::errs() << "[" << index++ << "]  ";
-    (*I)->dump();
+    Piece->dump();
     llvm::errs() << "\n";
   }
 }
diff --git a/clang/lib/Analysis/ReachableCode.cpp b/clang/lib/Analysis/ReachableCode.cpp
index 739c47b12e8c..4a9ab5d9f0f7 100644
--- a/clang/lib/Analysis/ReachableCode.cpp
+++ b/clang/lib/Analysis/ReachableCode.cpp
@@ -460,9 +460,8 @@ static bool isInCoroutineStmt(const Stmt *DeadStmt, const CFGBlock *Block) {
   const Stmt *CoroStmt = nullptr;
   // Find the first coroutine statement after the DeadStmt in the block.
   bool AfterDeadStmt = false;
-  for (CFGBlock::const_iterator I = Block->begin(), E = Block->end(); I != E;
-       ++I)
-    if (std::optional<CFGStmt> CS = I->getAs<CFGStmt>()) {
+  for (const CFGElement &Elem : *Block)
+    if (std::optional<CFGStmt> CS = Elem.getAs<CFGStmt>()) {
       const Stmt *S = CS->getStmt();
       if (S == DeadStmt)
         AfterDeadStmt = true;